115 lines
2.5 KiB
JavaScript
115 lines
2.5 KiB
JavaScript
'use strict';
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const debug = require('debug')('detect-port');
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const net = require('net');
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const address = require('address');
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module.exports = (port, host, callback) => {
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if (typeof port === 'function') {
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callback = port;
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port = null;
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} else if (typeof host === 'function') {
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callback = host;
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host = null;
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}
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port = parseInt(port) || 0;
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let maxPort = port + 10;
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if (maxPort > 65535) {
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maxPort = 65535;
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}
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debug('detect free port between [%s, %s)', port, maxPort);
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if (typeof callback === 'function') {
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return tryListen(host, port, maxPort, callback);
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}
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// promise
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return new Promise((resolve, reject) => {
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tryListen(host, port, maxPort, (error, realPort) => {
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if (error) {
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reject(error);
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} else {
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resolve(realPort);
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}
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});
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});
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};
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function tryListen(host, port, maxPort, callback) {
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function handleError() {
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port++;
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if (port >= maxPort) {
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debug(
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'port: %s >= maxPort: %s, give up and use random port',
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port,
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maxPort
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);
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port = 0;
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maxPort = 0;
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}
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tryListen(host, port, maxPort, callback);
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}
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// 1. check specified host (or null)
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listen(port, host, (err, realPort) => {
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// ignore random listening
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if (port === 0) {
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return callback(err, realPort);
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}
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if (err) {
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return handleError(err);
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}
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// 2. check default host
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listen(port, null, err => {
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if (err) {
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return handleError(err);
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}
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// 3. check localhost
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listen(port, 'localhost', err => {
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if (err) {
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return handleError(err);
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}
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// 4. check current ip
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let ip;
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try {
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ip = address.ip();
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} catch (err) {
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// Skip the `ip` check if `address.ip()` fails
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return callback(null, realPort);
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}
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listen(port, ip, (err, realPort) => {
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if (err) {
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return handleError(err);
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}
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callback(null, realPort);
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});
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});
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});
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});
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}
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function listen(port, hostname, callback) {
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const server = new net.Server();
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server.on('error', err => {
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debug('listen %s:%s error: %s', hostname, port, err);
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server.close();
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if (err.code === 'ENOTFOUND') {
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debug('ignore dns ENOTFOUND error, get free %s:%s', hostname, port);
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return callback(null, port);
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}
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return callback(err);
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});
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server.listen(port, hostname, () => {
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port = server.address().port;
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server.close();
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debug('get free %s:%s', hostname, port);
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return callback(null, port);
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});
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}
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